Electromechanical actuators based on conducting polymers are known in the art and find use as artificial muscles as well as in a myriad of other applications. Operation of such actuators is achieved by redox processes. The actuators may be arranged for providing a bending motion or a uniaxial force.
The bending or axial force is achieved as a result of volume changes in the conducting polymer upon application of a potential to the polymer. More particularly, the volume changes occur as a result of the injection or expulsion of counter ions into or from the polymer during these processes. For instance, upon electrochemically oxidizing a neutral conducting polymer film by the application of an anodic potential to the polymer in an electrolyte, positive charges are generated along the polymer resulting in counter ions being forced to enter the polymer from the electrolyte. As a result, there may be a significant increase in the volume of the conducting polymer. During reduction with a change in the potential, electrons are injected into the solid eliminating the positive charges and forcing the counter ions and solvated molecules to be expelled into the electrolyte. The result of this is that the volume of the conducting polymer decreases and the polymer returns to its neutral state. By harnessing the changes in volume, the electromechanical actuator can be utilized to achieve the desired action such as in the case of an artificial muscle. The expansion and contraction movement of the conducting polymer may also be utilized such as for example, for operating a piston in a miniature pump and other mechanical type applications.
However, attempts to improve the efficiency of performance of electromechanical actuators can impact on the mechanical and/or electromechanical properties of the actuator. It is, therefore, desirable to enhance efficiency of performance while minimizing any impact on the mechanical and/or electromechanical properties of such actuators.